Key Highlights

  • Glaukos (NYSE:GKOS) surged 33.7 percent on October 29, 2026, the largest gain on a closing list of movers. Alnylam (NASDAQ:ALNY) fell 25.1 percent the same day, and the cause of both moves has not been confirmed.
  • ADT (NYSE:ADT) jumped about 34 percent to roughly USD 9.93 on October 29, 2026, after Thrive Holdings offered USD 10 per share in cash, a bid valuing the company at about USD 7.6 billion. The terms come from one account.
  • Crocs (NASDAQ:CROX) climbed about 25 percent on October 29, 2026, reaching its highest level in more than two years. HeyDude Revenue grew 6.1 percent to USD 170 million, and the company lifted its 2026 guidance for the third time.
  • Sprouts Farmers Market (NASDAQ:SFM) dropped between 18 percent and 22.6 percent on October 29, 2026, after the grocer lowered its fourth-quarter outlook, with published accounts giving different figures. Management reportedly cautioned that price cuts will weigh on profit into next year.

Glaukos (NYSE:GKOS): Largest gain, no confirmed cause

Glaukos (NYSE:GKOS), a maker of eye-care devices and therapies, surged 33.7 percent on October 29, 2026. Alnylam (NASDAQ:ALNY), a pioneer in RNA interference medicines, fell 25.1 percent. Both appear on a single closing list of S&P-adjacent stocks, so the figures carry a one-account flag. Moves of 25 percent to 34 percent within one session are rare for companies of this size and usually point to company-specific news such as results, guidance or a clinical or regulatory update. However, the cause was not verified for either company, so this article treats the moves as facts and the reasons as unknown. Neither company's results, guidance or analyst notes were confirmed in the published accounts, so even the nature of the news behind each move is unknown. The closing list is described as covering the biggest winners and losers, which makes the pairing a market-wide snapshot. In MedTech and biotech, a single data point can change how investors value future revenue. For a device maker, a shift in procedure volumes, reimbursement or product launches can alter Earnings forecasts. For an RNAi biotech, product sales, trial readouts or competitive data can do the same. A drop of 25.1 percent typically means expectations were high and something fell short, while a gain of 33.7 percent suggests results or guidance cleared a low bar.

ADT (NYSE:ADT): Cash bid under USD 10

ADT (NYSE:ADT) said on October 29, 2026 that Thrive Holdings had offered USD 10 per share in an all-cash deal valuing the company at about USD 7.6 billion. The shares jumped roughly 34 percent to about USD 9.93. The existence of an 8-K filing and proxy filings is confirmed, but their text could not be opened, so the terms rest on one published account. The premium to the prior close, the closing timeline, the financing and any conditions are unverified and not stated. The rise of about 34 percent suggests the offer sat well above the earlier price, though the exact premium was not retrieved. With an all-cash offer, the target's shares usually trade a little below the bid. That gap, known as the spread, compensates holders for waiting until closing and for the chance the deal fails. Here ADT (NYSE:ADT) near USD 9.93 against USD 10 leaves about USD 0.07, or 0.7 percent, per share, which is simple arithmetic on two published numbers. A spread that narrow implies the market sees a high chance of completion and a short wait, though that is an inference and not a company statement.

Crocs (NASDAQ:CROX): Two-year high, third raise

Crocs (NASDAQ:CROX) reported third-quarter results on October 29, 2026, and the stock climbed about 25 percent to its highest level in more than two years. Three published accounts confirm the move and its main drivers. HeyDude, the company's second brand, grew revenue 6.1 percent to USD 170 million, its first increase in six quarters. Management also lifted its 2026 outlook for the third time this year. Consensus estimates, the new guidance ranges and the figures for the main Crocs Brand were not retrieved, so none is stated here. A one-day gain of about 25 percent is large for a consumer company, which is why the shares drew attention. A brand returning to growth after six quarters of declines changes how investors judge the business. HeyDude is the company's second brand, and six quarters without growth had kept attention fixed on it. A 6.1 percent rise is modest and comes from a small base, yet the direction matters because it hints that the brand may have stopped losing share. For Crocs (NASDAQ:CROX), a third guidance raise in one year also carries weight, since repeated upgrades usually signal that management set cautious targets.

Sprouts Farmers Market (NASDAQ:SFM): Outlook cut, wide range

Sprouts Farmers Market (NASDAQ:SFM) dropped between 18 percent and 22.6 percent on October 29, 2026, after lowering its fourth-quarter outlook. Reported EPS guidance of USD 0.47 to 0.51 was compared with an expected figure of about USD 1.21. That comparison holds up poorly, since a guide of roughly half the consensus would imply a far bigger collapse than the verified moves, so the USD 1.21 consensus is treated as unconfirmed. What is consistent is the direction: a guidance cut and a steep share decline. The different figures probably reflect different times of day. The company release is the best place to confirm the exact wording and ranges of the revised outlook. Grocers sometimes cut prices to defend traffic against rivals, and the trade-off is that each sale carries a thinner margin. Sprouts said price cuts will hurt profit into next year, which signals the pressure is not limited to one quarter. Investors had priced the stock for steady growth, so a warning that profitability will stay under strain can reset valuation quickly.

Where Things Stand

In short, the biggest moves of the session had very different drivers. ADT has an announced cash offer, Crocs has a return to growth at HeyDude and a third guidance raise, Sprouts has a lowered outlook, and Glaukos (NYSE:GKOS) has no confirmed cause at all. Large moves are not all alike: a bid caps the upside, a guidance raise tests the next quarter and a cut can compound. The next catalysts are the ADT proxy, the Crocs report, Sprouts releases and any news that explains Glaukos (NYSE:GKOS). This is not Investment advice.